import sys

def fact(n):
    
    if n == 0:
        return 1
    return n * fact(n-1)

def div(n):
    res= 10 / n
    return res

def main(n):
    res=fact(n)
    print(res)

if __name__=='__main__':
    if len(sys.argv) > 1:
        main(int(sys.argv[1]))
